The present invention relates to lighting systems and in particular to an improved lighting system for lighting a work area with reduced glare and veiling reflections.
In U.S. Pat. No. 4,054,793 issued Oct. 18, 1977 to Sylvan R. Shemitz there is disclosed a desk level work area lighting system. As set forth in that patent, the object of such systems is to provide lighting whereby direct glare and veiling reflections are substantially eliminated from a task positioned at the work area. For this reason such lighting systems are commonly referred to as "task" lighting. The Shemitz patent utilizes a light fixture positioned above a desk. Light from a linear source (i.e., such as an elongated fluorescent tube) is reflected through a refractor member having prisms extending perpendicular to the light source. In order to reduce direct glare and veiling reflections on the desk top surface, the half bat wing configuration of luminous flux eminating from the fixture is directed to the right and left by the refractor member.
The sacrifice paid for eliminating glare and veiling reflections from the center of the work area is decreased illumination at the extremes of the desk. That is, when a person is sitting at the center of the desk and looks to his right or left, those areas will appear abnormally dark. To overcome this problem, the copending application Ser. No. 891,697 for Improved Work Area Lighting System commonly assigned with the present application proposes an arrangement of refractor plates which permits light flux distribution to be varied over the desk top as may be required. While improving the end-to-end light distribution there is some loss of front to back distribution. While the light could be spread by tilting the fixture, such tilting would pose problems of glare. That is, some fixtures are designed to permit their light sources to be tilted to throw out the light however, this may result in the bulb being exposed directly to the eyes of the worker at the station, particularly with low fixtures which would result in harsh glare.
In view of the above, it is the principal object of the present invention to provide an improved lighting system for a desk level work station capable of providing reduced direct glare and veiling reflections to the work station, while providing substantially uniform light distribution over the entire work station both from end-to-end and front to back.
A further object is to provide such a system which permits a lamp to be mounted closely to the top of a work surface and yet throws substantial light over the entire work surface.
Further objects and advantages will become evident from the following specification.